Method and device for transmitting and receiving signal in wireless communication system

ABSTRACT

Provided are a method and device for transmitting and receiving a signal in a wireless communication system. In a wireless communication system according to an embodiment of the present disclosure, a radio unit (RU) is configured to obtain channel information about a plurality of reception paths of the RU, through which signals of at least one user equipment (UE) are received, with respect to each UE, determine a combined weight based on the channel information by using preset mapping information according to the number of the plurality of reception paths and the number of combined paths that are combined from the plurality of reception paths, and transmit a combined signal to a digital unit (DU) through the combined paths, the combined signal being generated as a result of combining the signals received through the plurality of reception paths according to the determined combined weight.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method and device for transmitting and receivinga signal in a wireless communication system.

BACKGROUND ART

To meet the increase in demand with respect to wireless data trafficafter the commercialization of 4^(th) Generation (4G) communicationsystems, considerable efforts have been made to develop improved 5^(th)Generation (5G) communication systems or pre-5G communication systems.For this reason, 5G communication systems or pre-5G communicationsystems are called beyond 4G network communication systems or post LongTerm Evolution (LTE) systems. To achieve a high data rate, theimplementation of 5G communication systems in an ultra-high frequencymillimeter wave (mmWave) band (e.g., a 60 GHz band) is underconsideration. To alleviate propagation path loss of radio waves andincrease propagation distances of radio waves in an ultra-high frequencyband, technologies for 5G communication systems, such as beamforming,massive multiple input multiple output (MIMO), full dimensional MIMO(FD-MIMO), array antenna, analog beamforming, and large-scale antennatechnologies are discussed. Also, in order to improve a system networkfor 5G communication systems, the development of techniques, such asevolved small cell, advanced small cell, cloud radio access network(cloud RAN), ultra-dense network, Device-to-Device (D2D) communication,wireless backhaul, moving network, cooperative communication,Coordinated Multi-Points (CoMP), and reception interferencecancellation, has been conducted. In addition, for 5G communicationsystems, hybrid Frequency Shift Keying (FSK) and Quadrature AmplitudeModulation (QAM) (FQAM) and Sliding Window Superposition Coding (SWSC),which are Advanced Coding Modulation (ACM) schemes; and Filter BankMulti-Carrier (FBMC), Non-Orthogonal Multiple Access (NOMA), and SparseCode Multiple Access (SCMA), which are advanced access techniques, havebeen developed.

The Internet has evolved from a human-centered connection network,through which a human generates and consumes information, to an Internetof Things (IoT) network that exchanges and processes information betweendistributed elements such as objects. Internet of Everything (IoE)technology is emerging, in which technology related to the IoT iscombined with, for example, technology for processing big data throughconnection with a cloud server. In order to implement the IoT, varioustechnical components are required, such as a sensing technique,wired/wireless communication and network infrastructures, a serviceinterfacing technique, a security technique, etc. In recent years,techniques including a sensor network for connecting objects,Machine-to-Machine (M2M) communication, Machine Type Communication(MTC), etc., have been studied. In the IoT environment, intelligentInternet Technology (IT) services may be provided to collect andinterpret data obtained from objects connected to each other, and tocreate new value in human life. As existing information technology (IT)and various industries converge and combine with each other, the IoT maybe applied to various fields, such as smart homes, smart buildings,smart cities, smart cars or connected cars, smart grids, health care,smart home appliances, high quality medical services, etc.

Various attempts are being made to apply 5G communication systems to IoTnetworks. For example, technologies related to sensor networks, M2Mcommunication, MTC, etc., are implemented by using 5G communicationtechnology including beamforming, MIMO, array antennas, etc. Theapplication of cloud RAN as the big data processing technique describedabove may be an example of convergence of 5G communication technologyand IoT technology.

As it is possible to provide various services according to thedevelopment of wireless communication systems, there is a need for amethod of efficiently providing these services.

DESCRIPTION OF EMBODIMENTS Technical Problem

The present disclosure provides a method and device for transmitting andreceiving a signal in a wireless communication system in which a radiounit and a digital unit are present at different positions, whereinresources required to transmit a signal from the radio unit to thedigital unit may be effectively reduced through path combination.

Solution to Problem

The present disclosure relates to a method and device for transmittingand receiving a signal in a wireless communication system. In a wirelesscommunication system according to an embodiment of the presentdisclosure, a radio unit (RU) is configured to obtain channelinformation about a plurality of reception paths of the RU, throughwhich signals of at least one user equipment (UE) are received, withrespect to each UE, determine a combined weight based on the channelinformation by using preset mapping information according to the numberof the plurality of reception paths and the number of combined pathsthat are combined from the plurality of reception paths, and transmit acombined signal to a digital unit (DU) through the combined paths, thecombined signal being generated as a result of combining the signalsreceived through the plurality of reception paths according to thedetermined combined weight.

Advantageous Effects of Disclosure

According to embodiments described herein, reception paths are combinedthrough a combined weight in a multiple antenna communication systemhaving a large number of reception paths of a radio unit, such that theamount of information transmitted from the radio unit to a digital unitmay be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram for describing a method, performed by aradio unit (RU), of transmitting a signal to a digital unit (DU) througha combined path, according to an embodiment.

FIG. 2 is a diagram for describing a combined signal when a weight isdetermined regardless of channel characteristics of a reception path inan RU.

FIG. 3 is a flowchart of a method, performed by an RU, of transmittingand receiving a signal, according to an embodiment.

FIG. 4 is a diagram for describing a method, performed by an RU, ofdetermining a combined weight, according to an embodiment.

FIG. 5 is a diagram for describing a combined weight generated by an RU,according to an embodiment.

FIG. 6 is a diagram for describing a method, performed by an RU, ofgenerating a combined weight based on channel information that is a 4×32matrix, according to an embodiment.

FIG. 7 is a block diagram of an RU according to an embodiment.

BEST MODE

According to an embodiment of the present disclosure, a method,performed by a radio unit (RU), of transmitting and receiving a signalin a wireless communication system includes: obtaining channelinformation about a plurality of reception paths of the RU, throughwhich signals of at least one user equipment (UE) are received, withrespect to each UE; determining a combined weight based on the channelinformation by using preset mapping information according to the numberof the plurality of reception paths and the number of combined pathsthat are combined from the plurality of reception paths; andtransmitting a combined signal to a digital unit (DU) through thecombined paths, the combined signal being generated as a result ofcombining the signals received through the plurality of reception pathsaccording to the determined combined weight.

In the method according to the embodiment, when the number of theplurality of reception paths is N and the number of the combined pathsis M, the combined weight may be a matrix including M×N combined weightvectors.

In the method according to the embodiment, the determining of thecombined weight may include mapping a channel vector constitutingchannel information about a plurality of reception paths to M×N combinedweight vectors by using the preset mapping information.

In the method according to the embodiment, the obtaining of the channelinformation may include obtaining the channel information based on arandom access signal transmitted by the at least one UE when the atleast one UE connects to the RU for an initial call.

In the method according to the embodiment, the obtaining of the channelinformation may include obtaining the channel information byperiodically receiving a sounding reference signal (SRS) from the atleast one UE.

In the method according to the embodiment, the obtaining of the channelinformation may include obtaining the channel information through ademodulation reference signal (DMRS) received through a data channelbetween the at least one UE and the RU.

The method according to the embodiment may further include obtaining,through a physical uplink shared channel (PUSCH), information about thenumber of allocated layers between the at least one UE and the RU andinformation about UEs allocated to a specific layer, and the obtainingof the channel information may include obtaining channel informationabout a plurality of reception paths for each UE based on theinformation about the number of allocated layers and the informationabout the UEs allocated to the specific layer.

The method according to the embodiment may further include obtaininginformation about the number of UEs allocated per resource block (RB)through a physical uplink shared channel (PUSCH).

In the method according to the embodiment, the determining of thecombined weight may include, when UEs scheduled for each RB in afrequency domain are different, determining the combined weight based onchannel information obtained in each RB in the frequency domain.

According to an embodiment, a radio unit (RU) for transmitting andreceiving a signal in a wireless communication system includes: at leastone processor configured to obtain channel information about a pluralityof reception paths of the RU, through which signals of at least one userequipment (UE) are received, with respect to each UE, and determine acombined weight based on the channel information by using preset mappinginformation according to the number of the plurality of reception pathsand the number of combined paths that are combined from the plurality ofreception paths; a transceiver configured to transmit a combined signalto a digital unit (DU) through the combined paths, the combined signalbeing generated as a result of combining the signals received throughthe plurality of reception paths according to the determined combinedweight; and a memory configured to store the preset mapping information.

MODE OF DISCLOSURE

Hereinafter, technology for a terminal to receive broadcast informationfrom a base station in a wireless communication system will bedescribed. The present disclosure relates to a communication techniquefor converging, with an Internet of Things (IoT) technology, a 5^(th)Generation (5G) communication system for supporting a data transmissionrate higher than that of a 4^(th) Generation (4G) system or a beyond 4Gsystem, and a system therefor. The present disclosure may be applied tointelligent services based on 5G communication technology andIoT-related technology (e.g., smart homes, smart buildings, smartcities, smart cars or connected cars, health care, digital education,retail, security and safety related services, etc.).

For convenience of description, some terms and names defined in the 3rdGeneration Partnership Project Long-Term Evolution (3GPP LTE) standardmay be used. However, the present disclosure is not limited by the termsand names and may be equally applied to systems conforming to otherstandards.

A wireless communication system has evolved from a system providing avoice-oriented service to a broadband wireless communication systemproviding high-speed high quality packet data services of communicationstandards such as High Speed Packet Access (HSPA) of 3GPP, LTE orEvolved Universal Terrestrial Radio Access (E-UTRA), LTE-A, LTE-Pro,High Rate Packet Data (HRPD) of 3GPP2, Ultra Mobile Broadband (UMB), andIEEE 802.16e.

As a representative example of the broadband wireless communicationsystem, the LTE system employs an Orthogonal Frequency DivisionMultiplexing (OFDM) scheme in a downlink (DL) and employs a SingleCarrier Frequency Division Multiple Access (SC-FDMA) scheme in an uplink(UL). The UL refers to a radio link through which a terminal (userequipment (UE) or mobile station (MS)) transmits data or a controlsignal to a base station (eNode B or BS), and the DL refers to a radiolink through which a BS transmits data or a control signal to a UE. Inthe multiple access scheme as described above, data or controlinformation for each user may be distinguished by performing allocationand operation so that time-frequency resources for carrying data orcontrol information for each user do not overlap each other, that is,orthogonality is established.

Future communication systems after LTE, that is, 5G communicationsystems (or New Radio (NR)) have to be able to freely reflect variousrequirements of users and service providers. Therefore, services thatsatisfy various requirements at the same time have to be supported.Services considered for 5G communication systems include enhanced MobileBroadband (eMBB), massive machine Type Communication (MMTC), and UltraReliability Low Latency Communication (URLLC).

Hereinafter, embodiments of the present disclosure, which are applicableto the above-described communication systems, will be described indetail with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram for describing a method, performed by aradio unit (RU), of transmitting a signal to a digital unit (DU) througha combined path, according to an embodiment.

In general, a BS may largely include an RU and a DU. The DU may includea digital device that processes a baseband signal, and the RU mayinclude an analog device that processes an analog radio signal.

An RU and a DU may be present in one cell site. However, in a structuresuch as a centralized/cloud radio access network (C-RAN), an RU and a DUmay be separated, only the RU is left in a cell site in which an actualradio signal is transmitted and received, and the DU present in eachcell site may be managed in a centralized manner. The RU and the DUprovided at different places may be connected to each other via anoptical cable.

When the RU and the DU are provided at different places, an RU-DUinterface for transmitting and receiving information between the RU andthe DU may be present. A signal that the RU receives from at least oneUE through the RU-DU interface may be transmitted to the DU. When thereare a plurality of reception paths for a radio signal received from theUE, the amount of information to be transmitted through the RU-DUinterface may increase. In this case, as a bandwidth (BW) requiredbetween the RU and the DU increases, a front haul construction cost mayincrease. The reception path indicates a path through which a signal istransmitted in an UL between at least one UE and the RU.

In a wireless communication system 100 according to an embodiment, as inmassive multiple input multiple out (MIMO), when an RU 110 having aplurality of reception paths transmits a signal to a DU 120, thereception paths are combined to reduce the amount of information of asignal transmitted from the RU 110 to the DU 120.

Referring to FIG. 1, a signal that the RU 110 receives from at least oneUE through N antennas 112 may pass through at least one module 114including a radio frequency (RF) receiver (a filter or a low noiseamplifier (LNA)), a down conversion module, and an analog-to-digitalconverter (ADC). The signal received from the at least one UE throughthe at least one module 114 may be subjected to the operation of the RFreceiver, down-converted into a base band, and then converted into adigital signal. However, the at least one module 114 illustrated in FIG.1 is only an example, and other types of modules that perform theabove-described operations may be included in the RU 110.

In order to reduce the amount of information of the signal convertedthrough the at least one module 114, the RU 110 may determine a combinedweight for combining the reception paths based on channel informationabout the reception paths. For example, in order to combine N receptionpaths, which are paths through which signals are received from the atleast one UE, into M paths, the RU 110 may determine an M×N matrixincluding a combined weight vector based on channel information about aplurality of reception paths for each UE. In the present disclosure, themethod of determining the combined weight will be described below inmore detail with reference to FIGS. 3 to 7.

The RU 110 may generate a combined signal by combining signals receivedfrom the at least one UE through the N reception paths according to thecombined weight. The RU 110 may transmit the generated combined signalto the DU 120 through the M combined paths.

The DU 120 may recover data through digital signal processing from thesignals received through the M combined paths.

FIG. 2 is a diagram for describing a combined signal when a weight isdetermined regardless of channel characteristics of a reception path inan RU.

Referring to FIG. 2, the RU may determine a combined weight 210 forcombining reception paths regardless of channel characteristics of thereception paths. For example, the RU may use the combined weight 210,which is an 8×32 matrix, so as to generate 8 combined paths from 32reception paths. Also, it is assumed that the RU determines [1, 1, 1, 1]as the combined weight vector for the reception paths grouped by four inthe 8×32 matrix. In the 8×32 matrix, 0 may be applied to a part notspecified as 1.

When the RU combines the reception paths regardless of the channelcharacteristics of the reception paths, the amount of informationobtained by the DU may be lost. For example, when instantaneous channelcharacteristics of the reception paths of the RU are [1, −1, 1, −1], thecomponents of the combined path may be canceled according to Equation 1below.

[1,−1,1,−1]×[1,1,1,1]^(T) =O  Equation 1

As in the above-described example, when the components of the combinedpath are canceled, it may be difficult to recover the signals in the DU.Therefore, it is necessary to determine a combined weight that iscapable of preventing loss of signals while reducing a BW between the RUand DU.

In the wireless communication system according to the embodiment, the RUdetermines the combined weight considering channel characteristics ofthe reception paths, thereby reducing loss of signals transmitted fromthe RU to the DU. Details thereof will be described below with referenceto FIGS. 3 to 7.

FIG. 3 is a flowchart of a method, performed by the RU, of transmittingand receiving a signal, according to an embodiment.

In operation 310, the RU may obtain channel information about aplurality of reception paths, through which signals of at least one UEare received, with respect to each UE.

The RU according to the embodiment may obtain channel information basedon a random access signal transmitted when at least one UE connects tothe RU for an initial call. For example, the RU may obtain channelinformation from a signal received through a physical random accesschannel (PRACH).

According to another embodiment, the RU may obtain channel informationbased on a sounding reference signal (SRS) periodically received fromthe at least one UE. According to another embodiment, the RU may obtainchannel information through a demodulation reference signal (DMRS)received through a data channel between the at least one UE and the RU.

The RU may obtain channel information for each UE considering the numberof layers allocated for each UE. For example, the RU may obtaininformation about the number of allocated layers between the at leastone UE and the RU and information about UEs allocated to a specificlayer through a physical uplink shared channel (PUSCH). According toanother example, the RU may obtain information about the number of UEsallocated per resource block (RB) through a physical uplink controlchannel (PUCCH). In particular, when UEs scheduled for each RB of afrequency domain are different as in the OFDM system, the number of UEsallocated for each RB may be different. Therefore, the RU may determinethe number of UEs allocated for each RB through the PUCCH.

In operation 320, the RU may determine a combined weight based onchannel information by using preset mapping information according to thenumber of reception paths and the number of combined paths that arecombined from the reception paths.

For example, when the number of reception paths between the at least oneUE and the RU is N and the number of combined paths between the RU andthe DU is M, a matrix including an M×N combined weight vector may berequired as the combined weight so as to generate M combined paths fromN reception paths. The RU may map each channel vector constitutingchannel information about a plurality of reception paths to M×N combinedweight vectors by using the preset mapping information. The mappinginformation may include an index of the channel vector, an index of theweight vector, and a value (e.g., 0 or 1) applied to the channel vector,but this is only an example. The mapping information is not limited tothe above-described example.

Because the number of UEs simultaneously allocated to the RB isdifferent for each RB, mapping information may be configured differentlyaccording to the RB.

In operation 330, the RU may transmit a combined signal to the DUthrough the combined path, the combined signal being generated as aresult of combining the signals received through the reception pathsaccording to the determined combined weight.

The RU according to the embodiment may generate the combined signal byapplying the combined weight to the signals obtained through thereception paths. The RU may effectively reduce the BW required betweenthe RU and the DU by combining the reception paths by using the combinedweight generated considering the channel characteristics.

The DU may recover data through digital signal processing from thesignals received through the M combined paths.

FIG. 4 is a diagram for describing a method, performed by the RU, ofdetermining a combined weight, according to an embodiment.

Referring to FIG. 4, the RU may obtain channel information about aplurality of reception paths, through which signals of at least one UEare received, with respect to each UE. When the UE includes one antennaand the RU includes N antennas, channel information for the UE may berepresented by a 1×N matrix.

Also, the RU may obtain pieces of channel information as many as thenumber of UEs simultaneously allocated to the RB. For example, when thenumber of simultaneously allocated UEs is L, the RU may obtain h1, h2, .. . , hL, which are vectors having L 1×N components. This is only anexample of a case in which a signal is transmitted to one layer per UE.When a signal is transmitted to two layers per UE, a vector having L/22×N components may be obtained. It is assumed that L is less than orequal to M, which is the number of combined paths.

The RU may obtain preset mapping information according to the number Nof reception paths and the number M of combined paths. According toblock 410, the RU may obtain A_(L), B_(L), and C_(L), which are indicesfor specifying the UE, from the preset mapping information andsubstitute A_(L), B_(L), and C_(L) into A, B, and C, respectively. a(i,j), which is a component of a matrix A into which A_(L) is substituted,may have a value from 1 to L. b(i, j), which is a component of a matrixB into which B_(L) is substituted, may have a value from 1 to N. c(i,j), which is a component of a matrix C into which C_(L) is substituted,may have 0 or 1. Also, an initial combined weight W may be set to zero.

According to block 420, the RU may use the above-described indices todetermine, as a component of a combined weight matrix W, a channel valueor 0 with respect to a reception path for each UE during L×N times.According to the preset value of c(i, j), when the component of c(i, j)is 0, the component of the combined weight matrix W may be determined tobe 0, and when the component of c(i, j) is 1, the channel value may besubstituted as the component of the combined weight matrix W.

According to block 430, the RU may normalize the magnitude of thecombined weight so as to maintain signal strength in the combined path.

According to block 440, the RU may combine a signal r received through aplurality of reception paths according to the combined weight matrix Wfinally obtained as a result of the normalizing. The RU may transmit acombined signal y obtained as a result of the combining to the DUthrough M combined paths.

FIG. 5 is a diagram for describing a combined weight generated by theRU, according to an embodiment.

Referring to FIG. 5, the RU may determine an N×M combined weight matrixW so as to derive M combined paths from N reception paths. In thepresent embodiment, it is assumed that the number of UEs simultaneouslyallocated to the RB is L and a vector h representing channel informationfor each UE includes 1×N components.

The RU may apply channel information for each UE as each component ofthe combined weight matrix according to preset mapping information. Forexample, group 1 410 to which channel information of UE 1 is mapped inthe combined weight matrix W may include h′(1, 1), h′(1, 2), h′(1,m(1)), and 0. h′(1, 1), h′(1, 2), and h′(1, m(1)) may be determined fromat least some components of a matrix representing the channelinformation about UE 1. Also, in order to maintain signal strength inthe combined path, the RU may perform normalization after mapping atleast some components of the vector indicating the channel informationabout UE 1 to components of the combined weight matrix W.

Also, as described above, the combined weight matrix W may furtherinclude groups 2 to group L 420 to which channel information about UE 2to UE L is mapped.

The RU according to the embodiment may use the generated M×N combinedweight matrix to combine the signals received through the N receptionpaths so as to be transmitted through the M combined paths.

FIG. 6 is a diagram for describing a method, performed by the RU, ofgenerating a combined weight based on channel information that is a 4×32matrix, according to an embodiment.

In FIG. 6, an example of generating the combined weight matrix by usingthe mapping information described above with reference to FIG. 4 will bedescribed.

In the present embodiment, when a signal is transmitted to the RUthrough one layer per UE, a 4×32 matrix indicating channel informationabout four UEs may be obtained. In the present embodiment, it is assumedthat the number of antennas of the RU is 32 and the number of combinedpaths indicating the paths between the RU and the DU is 8.

In order to combine the reception paths, the RU according to theembodiment may determine an 8×32 combined weight matrix 610 based on a4×32 channel matrix indicating channel information. In the combinedweight matrix 610, h′(i) may be a vector including the first 16components of a channel vector h(i) of an i-th layer, and h″(i) may be avector including the remaining 16 components of the channel vector h(i)of the i-th layer. Also, in the combined weight matrix 610, 0 may be a16×1 zero vector.

When UEs scheduled for each RB in a frequency domain are different as inthe OFDM system, the above-described process may be performed for eachRB. To this end, the RU may perform a fast Fourier transform (FFT) on areceived signal before performing the combination.

FIG. 7 is a block diagram of an RU 700 according to an embodiment.

Referring to FIG. 7, the RU 700 may include a transceiver 710, aprocessor 720, and a memory 730. The transceiver 710, the processor 720and the memory 730 may operate according to the bandwidth adjustmentmethod of the BS proposed in the above-described embodiments. However,the elements of the RU 700 according to the embodiment are not limitedto the above-described example. According to another embodiment, the RU700 may include more elements or fewer elements than the above-describedelements. In a particular case, the transceiver 710, the processor 720,and the memory 730 may be implemented in the form of a single chip.

The transceiver 710 may transmit and receive a signal with a UE or a DU.The signal may include control information and data. To this end, thetransceiver 710 may include an RF transmitter that performsup-conversion and amplification on a frequency of a signal to betransmitted, and an RF receiver that performs low-noise amplification ona received signal and performs down-conversion on a frequency of thereceived signal. However, this is merely an embodiment, and the elementsof the transceiver 710 are not limited to the RF transmitter and the RFreceiver.

Also, the transceiver 710 may receive a signal through a radio channel,output the received signal to the processor 720, and transmit an outputsignal of the processor 720 through the radio channel. For example, thetransceiver 710 may transmit signals received from at least one UEthrough N reception paths by using M combined paths.

The processor 720 may control a series of processes so that the RU 700operates according to the above-described embodiments of the presentdisclosure. For example, the processor 720 may perform at least onesignal transmission and reception method according to theabove-described embodiments.

For example, the processor 720 may obtain channel information about aplurality of reception paths of the RU, through which signals of atleast one UE are received, with respect to each UE. Also, the processor720 may determine a combined weight based on channel information byusing preset mapping information according to the number of receptionpaths and the number of combined paths that are combined from thereception paths.

For example, the processor 720 may map a channel vector constitutingchannel information about a plurality of reception paths to M×N combinedweight vectors by using the preset mapping information.

The processor 720 may obtain channel information based on a randomaccess signal transmitted when at least one UE connects to the RU for aninitial call. According to another embodiment, the processor 720 mayobtain channel information by periodically receiving an SRS from the atleast one UE. According to another embodiment, the processor 720 mayobtain channel information through a DMRS received through a datachannel between the at least one UE and the RU.

Also, the processor 720 may obtain information about the number ofallocated layers between the at least one UE and the RU and informationabout UEs allocated to a specific layer through a PUSCH. The processor720 may obtain channel information about a plurality of reception pathsfor each UE based on the information about the number of allocatedlayers and the information about the UEs allocated to the specificlayer. However, this is only an example, and the processor 720 mayobtain information about the number of UEs allocated per RB through thePUCCH.

When UEs scheduled for each RB in the frequency domain are different,the processor 720 according to the embodiment may determine a combinedweight based on channel information obtained in each RB in the frequencydomain.

The memory 730 may store control information or data included in thesignal obtained by the RU 700 and may have an area for storing datanecessary for the control of the processor 720, data generated duringthe control of the processor 720, and the like. For example, the memory730 may store preset mapping information for determining the combinedweight. Also, according to another embodiment, the memory 730 may storeinformation about the determined combined weight.

The memory 730 may be configured in various forms, such as read-onlymemory (ROM), random access memory (RAM), hard disk, compact discread-only memory (CD-ROM), and/or digital versatile disc (DVD).

The embodiments of the present disclosure, which are described in thespecification and drawings, are merely presented as specific examples soas to easily explain the technical contents of the present disclosureand help the understanding of the present disclosure and are notintended to limit the scope of the present disclosure.

That is, it will be obvious to those of ordinary skill in the art thatother modifications based on the technical idea of the presentdisclosure may be made. Also, the embodiments are divided forconvenience of description and may be combined and operated asnecessary. For example, part of embodiments 1, 2, 3, and 4 of thepresent disclosure may be combined with each other so that the BS andthe UE operate.

The device according to the embodiments may include a processor, amemory configured to store and execute program data, a permanent storagesuch as a disk drive, a communication port configured to communicatewith an external device, and user interface devices such as a touchpanel, keys, or buttons. The methods implemented by software modules oralgorithms may be stored on a computer-readable recording medium ascomputer-readable code or program commands executable on the processor.Examples of the computer-readable recording medium may include magneticstorage media (e.g., ROM, RAM, floppy disk, hard disk, etc.) and opticalreadable media (e.g., CD-ROM, DVD, etc.). The computer-readablerecording medium may also be distributed over network-coupled computersystems so that the computer-readable code is stored and executed in adistributed fashion. The media may be read by the computer, be stored inthe memory, and be executed by the processor.

The embodiments of the present disclosure may be represented byfunctional block configurations and various processing operations. Allor part of such functional blocks may be realized by any number ofhardware components and/or software components configured to performparticular functions. For example, the embodiments described herein mayemploy various integrated circuit components, such as memories,processing, logics, look-up tables, and the like, which may carry out avariety of functions under the control of one or more microprocessors orother control devices. Similar to the elements of the embodiments thatmay be carried out by using software programming or software elements,the embodiments described herein may be implemented by any programmingor scripting language such as C, C++, Java, assembler, or the like,including various algorithms that are implemented by any combination ofdata structures, objects, processes, routines or other programmingelements. Functional aspects may be implemented by algorithms that areexecuted on one or more processors. Also, the embodiments describedherein may employ any conventional techniques for electronic environmentconfiguration, signal processing, and/or data processing.

1. A method, performed by a radio unit (RU), of transmitting andreceiving a signal in a wireless communication system, the methodcomprising: obtaining channel information about a plurality of receptionpaths of the RU, through which signals of at least one user equipment(UE) are received, with respect to each UE; determining a combinedweight based on the channel information by using preset mappinginformation according to the number of the plurality of reception pathsand the number of combined paths that are combined from the plurality ofreception paths; and transmitting a combined signal to a digital unit(DU) through the combined paths, the combined signal being generated asa result of combining the signals received through the plurality ofreception paths according to the determined combined weight.
 2. Themethod of claim 1, wherein, when the number of the plurality ofreception paths is N and the number of the combined paths is M, thecombined weight is a matrix including M×N combined weight vectors. 3.The method of claim 1, wherein the obtaining of the channel informationcomprises obtaining the channel information based on a random accesssignal transmitted by the at least one UE when the at least one UEconnects to the RU for an initial call.
 4. The method of claim 1,wherein the obtaining of the channel information comprises obtaining thechannel information by periodically receiving a sounding referencesignal (SRS) from the at least one UE.
 5. The method of claim 1, whereinthe obtaining of the channel information comprises obtaining the channelinformation through a demodulation reference signal (DMRS) receivedthrough a data channel between the at least one UE and the RU.
 6. Themethod of claim 1, further comprising: obtaining, through a physicaluplink shared channel (PUSCH), information about the number of allocatedlayers between the at least one UE and the RU and information about UEsallocated to a specific layer, and wherein the obtaining of the channelinformation comprises obtaining channel information about a plurality ofreception paths for each UE based on the information about the number ofallocated layers and the information about the UEs allocated to thespecific layer.
 7. The method of claim 1, wherein the determining of thecombined weight comprises, when UEs scheduled for each resource block(RB) in a frequency domain are different, determining the combinedweight based on channel information obtained in each RB in the frequencydomain.
 8. A radio unit (RU) for transmitting and receiving a signal ina wireless communication system, the RU comprising: at least oneprocessor configured to: obtain channel information about a plurality ofreception paths of the RU, through which signals of at least one userequipment (UE) are received, with respect to each UE, and determine acombined weight based on the channel information by using preset mappinginformation according to the number of the plurality of reception pathsand the number of combined paths that are combined from the plurality ofreception paths; a transceiver configured to transmit a combined signalto a digital unit (DU) through the combined paths, the combined signalbeing generated as a result of combining the signals received throughthe plurality of reception paths according to the determined combinedweight; and a memory configured to store the preset mapping information.9. The RU of claim 8, wherein, when the number of the plurality ofreception paths is N and the number of the combined paths is M, thecombined weight is a matrix including M×N combined weight vectors. 10.The RU of claim 8, wherein the at least one processor is furtherconfigured to obtain the channel information based on a random accesssignal transmitted by the at least one UE when the at least one UEconnects to the RU for an initial call.
 11. The RU of claim 8, whereinthe at least one processor is further configured to obtain the channelinformation by periodically receiving a sounding reference signal (SRS)from the at least one UE.
 12. The RU of claim 8, wherein the at leastone processor is further configured to obtain the channel informationthrough a demodulation reference signal (DMRS) received through a datachannel between the at least one UE and the RU.
 13. The RU of claim 8,wherein the at least one processor is further configured to: obtain,through a physical uplink shared channel (PUSCH), information about thenumber of allocated layers between the at least one UE and the RU andinformation about UEs allocated to a specific layer, and obtain channelinformation about a plurality of reception paths for each UE based onthe information about the number of allocated layers and the informationabout the UEs allocated to the specific layer.
 14. The RU of claim 8,wherein the at least one processor is further configured to, when UEsscheduled for each resource block (RB) in a frequency domain aredifferent, determine the combined weight based on channel informationobtained in each RB in the frequency domain.
 15. A computer-readablerecording medium having recorded thereon a program for executing themethod of claim 1 on a computer.